What is the Difference Between Box Jellyfish and True Jellyfish

The main difference between box jellyfish and true jellyfish is that box jellyfish has a box-shape medusa, whereas true jellyfish can have differently-shaped medusa. Furthermore, box jellyfish belongs to the class Cubozoa while true jellyfish belongs to the class Scyphozoa.  

Box jellyfish and true jellyfish are two classes of jellyfish with a prominent medusa stage in their life. Moreover, their umbrella-like body structure has trailing tentacles. 

Key Areas Covered 

1. Box Jellyfish
     – Taxonomy, Anatomical Features, Behavior
2. True Jellyfish
     – Taxonomy, Anatomical Features, Behavior
3. What are the Similarities Between Box Jellyfish and True Jellyfish
     – Outline of Common Features
4. What is the Difference Between Box Jellyfish and True Jellyfish
    – Comparison of Key Differences

Key Terms 

Box Jellyfish, Cnidaria, Eye, Medusa, Toxins, True Jellyfish

Box Jellyfish – Taxonomy, Anatomical Features, Behavior 

The box jellyfish is a cnidarian invertebrate that belongs to the class Cubozoa. The main distinguishing feature of these jellyfish is their cube-shaped medusae. Their medusae appear to be a square. Some species of box jellyfish, including Chironex fleckeri, Carukia barnesi, and Malo kingi, produce extremely potent venom. Further, their stings are extremely painful and can be fatal to large creatures, including humans. Therefore, they have a reputation for being one of the deadliest sea creatures in the world. 

Figure 1: Sea Wasp Jellyfish (Chironex sp.)

Furthermore, this jellyfish is a group of active hunters. Importantly, two main features make them active hunters. Firstly, they can move in a speed up to 2 meters per second through the water. Secondly, they have true eyes to see their prey. Generally, they have four sets of six eyes. Therefore, in total, they have 24 eyes. Additionally, each eye is complete with retinas, corneas, and lenses. 

True Jellyfish – Taxonomy, Anatomical Features, Behavior 

True jellyfish is another cnidarian invertebrate that belongs to the class Scyphozoa. Generally, they have a cup-shaped medusa, which is different from the cube-shaped medusae of box jellyfish. Also, they are the exclusively marine, common jellyfish. However, they do not have extremely potent toxins to kill large creatures.

Figure 2: Cauliflower Jellyfish (Cephea cephea)

Furthermore, true jellyfish is a slow-moving animal. It does not actively hunt its prey. But, they merely drift in the water and wait for their prey. Some true jellyfish only feed on planktons. When compared to the box jellyfish, true jellyfish do not have any sensory organ for visualization. 

Similarities Between Box Jellyfish and True Jellyfish 

• Box jellyfish and true jellyfish are two classes of jellyfish. 
• They belong to the phylum Cnidaria under the kingdom Animalia. 
• Also, both are invertebrates. 
• Generally, they inhabit the sea.  
• Medusa is their prominent life stage, which is their sexual stage. 
• Their umbrella-like bell is gelatinous.  
• Besides, their mouth or the only opening of the body occurs at the bottom side of the body. 
• Moreover, they have trailing tentacles around the mouth/anus, aiding their propulsion and capturing the prey. 
• Stinging cells or nematocytes in their tentacles help to capture the prey. 
• Both have paralyzing or sometimes, fetal toxins. 
• They have a nerve net in their epidermis. 
• Furthermore, they undergo external fertilization.  

Difference Between Box Jellyfish and True Jellyfish 

Definition 

Box jellyfish refers to the cnidarian invertebrates distinguished by their cube-shaped medusae while true jellyfish refers to the exclusively marine cnidarians, distinguished by the drinking cup-shaped organisms. Thus, this is the main difference between box jellyfish and true jellyfish.

Taxonomy 

Moreover, Box jellyfish belongs to the class Cubozoa while true jellyfish belongs to the class Scyphozoa. 

The shape of the Medusa

The box jellyfish has a cube-shaped medusa, while the true jellyfish can have different shapes of medusae. 

Toxins 

Another difference between box jellyfish and true jellyfish is the toxin. Most of the box jellyfish species have deadly toxins while the toxins in true jellyfish are less potent. 

Mobility 

Furthermore, Box jellyfish moves in a speed of 2 meters per second while true jellyfish moves slowly. 

Method of Hunting 

Box jellyfish actively hunts its prey while true jellyfish merely drifts in water, waiting for their prey.  

Visual Sensing 

Visual sensing is another major difference between box jellyfish and true jellyfish. The former has true eyes, while the latter does not have any organs for the visual sense.  

Conclusion 

Box jellyfish is a group of jellyfish classified under the class Cubozoa. Significantly, box jellyfish has a cube-shaped medusa. Also, they are active hunters that can move in considerably high speed. Additionally, they have true eyes to see their prey. Also, they have deadly toxins. On the other hand, true jellyfish is another group of jellyfish classified under the class Scyphozoa. However, they have different shapes of Medusa. Besides, they move slowly in water to capture their prey. Moreover, their toxins are less potent, and they do not have sensory organs for visualization. In summary, the main difference between box jellyfish and true jellyfish is their anatomical features and behaviour.  

References:

1. “Box Jellyfish.” New World Encyclopedia, Available Here.
2. “The True Jellyfish.” Introduction to the Scyphozoa, Available Here.

Image Courtesy:

1. “Avispa marina cropped” By Guido Gautsch, Toyota, Japanderivative work: Mithril (talk) (CC BY-SA 2.0) via Commons Wikimedia   
2. “Cauliflour Jellyfish, Cephea cephea at Marsa Shouna, Red Sea, Egypt SCUBA” By Derek Keats (CC BY-SA 2.0) via Commons Wikimedia